Masking tape is generally made utilizing paper which is impregnated with a latex. The paper is impregnated with latex to improve its physical properties and chemical resistance. This procedure incorporates a binder polymer from the latex into the paper to increase the tensile strength, tear resistance, delamination resistance, and water resistance of the paper. The impregnation procedure is normally done by passing the paper through a bath containing the latex for residence time which is sufficient for the paper to absorb the latex.
The paper having the binder polymer incorporated therein is then further processed into masking tape. In the procedure used one side of the paper is coated with a release coat. The other side of the paper is coated with an adhesive layer. Optionally the side of the paper which is coated with the adhesive is first coated with a primer coat and subsequently coated with an adhesive layer. The masking tape can then be rolled and packaged for later use.
Acrylic latices, carboxylated styrene-butadiene rubber latices, and acrylonitrile-butadiene latices are currently used industrially in the impregnation of paper which is employed in manufacturing masking tape. However, improved latices are desired for this purpose. It is highly desirable for the latex to be capable of being impregnated into the paper without encountering foaming or coagulum formation during normal processing. For instance, the shearing forces encountered during the impregnation procedures often cause coagulum formation with the coagulum building up on equipment rollers. It would be optimal to eliminate this problem while maintaining the physical and chemical properties desired for the paper. It is also important for the impregnated paper not to be sticky and to be non-blocking.